Well off, but bound by summons to where convict marks time (4,4)

'where convict marks time' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.

'well off but bound by summons' is the wordplay.
I cannot quite understand how this works, but
an anagram of 'well' is 'ellw' which is located in the answer.
'summons' could be 'call' (I've seen this in another clue) and 'call' is found in the leftover letters.
No letters remain.
This explanation may well be incorrect...

'to' acts as a link.

Can you help me to learn more?